glibc2.0-2.1 incompatibility: _xstat?

I have motif 2.0.1 and xrt libraries that define _xstat. This symbol is not defined
anymore in glibc-2.1; there, __xstat is defined. In glibc-2.0, _xstat is defined as
a weak alias for __xstat.
What does the weak_alias of _xstat mean?
Is there a workaround, so that I can continue to use these libraries?
Can someone more knowledgable shed some light on this?
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R. A. Hogendoorn E-mail: hogend@nlr.nl
Informatics Division Tel. +31-527-24-8367
National Aerospace Laboratory, The Netherlands Fax. +31-527-24-8210